This report describes the methodology and results of the East Africa hydrogeological case study, undertaken by University College London and the British Geological Survey. The aim of this case study is to investigate the resilience of intensive groundwater abstractions from weathered crystalline rock aquifer systems to climate change. The sustainability of such abstractions was investigated by examining historical aquifer responses to climate and intensive (> 1 L/s) abstraction, and investigating groundwater residence times at sites of intensive groundwater abstraction using multiple tracers: chlorofluorocarbons (CFCs), sulphur hexafluoride and tritium. This case study was carried out in Tanzania and Uganda.
This study indicates that sustainable larger supplies are often associated with a thick regolith (often including alluvium) over weathered basement rocks, and that yields of more than 1 l/s may be available in approximately 35% of effectively sited boreholes in these areas.
Maurice, L.; Taylor, R.; MacDonald, A.; Sanga, H.; Johnson, P.; Darling, G.; Gooddy, D. Case study note: Resilience of intensive groundwater abstraction from weathered crystalline rock aquifer systems to climate change in sub-Saharan Africa. British Geological Survey, Nottingham, UK (2010) 37 pp. [British Geological Survey Internal Report, XX/00/00]